The step of deboning an arm part or a thigh part (hereinafter referred to as a “work”) of a carcass to be supplied as meat such as pork, beef, and mutton roughly consists of a preliminary step of removing a hip bone and the like, a meat cutting step of making a cut in a longitudinal direction along the surface of a forearm bone, a humerus, a lower leg bone, or a thigh bone, and a meat separation step of tearing meat after the meat cutting step. Because the work is heavy, when the dissection and deboning operation is manually performed, heavy work is required. As a result, an operator has performed the deboning process while the work has been suspended by a suspension device such as a gambrel or a clamping device and transported, the heavy work has been still required.
Consequently, the present inventors propose a deboning unit in which the steps other than the preliminary step are automated in each of Patent Document 1 (WO 2008/136513A1) and Patent Document 2 (WO 2009/139032A1).
In the meat cutting step of the automated unit, when a bone buried in the meat of a work is removed while the work is suspended by the suspension device via an ankle, the total length of the bone of the work is measured with a clamping position by the suspension device used as a starting point. From the information on the total length, the outline of the buried bone is presumed based on an empirical rule. Next, a robot arm equipped with a cutting blade is operated to move the cutting blade along the presumed outline of the bone, and the meat cutting is thereby performed.
Although the method can handle about 80% of the total number of works, since the size of the work has an individual difference, in some cases, the bone has been left in the meat and the yield has been thereby reduced in the remaining 20% thereof. In addition, in some cases, the cutting blade has cut into the bone, an excessive load has been applied to the cutting blade, and the cutting blade has been damaged so that the deboning apparatus has had to be halted. The arm part and the thigh part of the carcass have many uneven variation points at its joint part and condyle part, and it is not easy to precisely operate the cutting blade along the surface of the bone at these parts when the individual difference in the work is large.
In the deboning step, although it is necessary to precisely cut body tissues such as a muscle and a tendon around the bone, a complicated arc-like shape of the bone completely buried in meat is not visible from the outside. In addition, due to a seasonal change in the state of fleshing or different states of fleshing of different farms, the size of the work itself varies so that there are cases where the muscle or the tendon cannot be cut completely in some works. Further, the above-described excessive load is applied to the cutting blade during the meat cutting in some movements of the robot arm, and hence the cutting blade has been operated on a safe side in which consideration has been given to an error resulting from the individual difference such that the excessive load has not been generated. As a result, in some cases, the yield of meat has been reduced.
Patent Document 3 discloses (Japanese Patent Application Laid-open No. H6-324006) a technical matter in which positions of a muscle of meat, a tendon, and a bone are read by using an X-ray irradiation unit, the positions thereof are indicated on two or more dimensional coordinates, and a cutting section is caused to perform a cutting operation on the basis of the process data.    [Patent Document 1] WO 2008/136513A1    [Patent Document 2] WO 2009/139032A1    [Patent Document 3] Japanese Patent Application Laid-open No. H6-324006
The technical matter disclosed in Patent Document 3 presents only the idea in which the positions of the muscle of the meat, the tendon, and the bone are read by using the X-ray irradiation unit and the result of the reading is utilized for the cutting of the muscle of the meat or the separation of the bone. Accordingly, even when the technical matter disclosed in Patent Document 3 is applied to the automated deboning unit disclosed in Patent Document 1 or 2, the above-described problem cannot be solved. That is, in order to allow a deboning process that does not generate the excessive load to the cutting blade, does not reduce operation efficiency, and maintains high yield to be performed on the work that has the complicated shape, is suspended, and rapidly moves at a constant speed or by feed based on a tact system, there are still many problems in terms of a production technology.